I heard someone say it best the other day. Jay Leno succeeded because he appealed to mainstream America. Conan failed to hold Leno's ratings because his "edgy" humor does not appeal to mainstream America. It's not that Conan isn't funny, but he's not funny enough to enough people. Whether Jimmy Fallon has, or can develop, the broadbased appeal of Johnny and Jay remains to be seen. At least his name begins with a "J".